How HR investigations should be conducted for workplace investigation

What is an HR investigation and when is it needed?

An investigation is needed when an employee raises a complaint about a colleague or manager, or when a manager has concerns about an employee’s conduct. Put simply, it is a process of gathering the facts so that the right decision can be made about what, if anything, should happen next.

A fair investigation matters. If an employee is later dismissed, an employment tribunal will ask whether the employer genuinely believed the employee was guilty of misconduct, whether it had reasonable grounds for that belief and whether it carried out as much investigation as was reasonable in the circumstances.

A rushed or one-sided investigation can make an otherwise justified dismissal unfair. From 1 January 2027, employees will be able to claim unfair dismissal after six months’ service rather than two years, so more investigations will be open to this kind of scrutiny.

Who should carry out the investigation?

There is no legal rule about who must investigate, but the investigator should be as impartial as possible and should have no personal involvement in the matter. The Acas Code of Practice on disciplinary and grievance procedures says that, where practicable, the person who investigates should not be the same person who conducts any later disciplinary hearing.

Investigators are often managers from another part of the business, with HR advising on the process, the legal risks and fairness. HR may carry out the investigation itself where the matter is particularly sensitive or the organisation is small. If nobody suitable is available internally, employers sometimes appoint an external investigator.

What makes a good investigator?

Knowledge

Investigators need a good understanding of the relevant policies and procedures, the employee’s role and the standards expected of it. Without this, it is hard to judge whether the conduct in question fell short.

Communication

Good investigators ask clear questions and follow up to fill any gaps. It helps to summarise what the person has said at the end of each topic and ask them to confirm it or add to it. Investigators should listen properly rather than simply working through a list of prepared questions.

Approachability

Investigation meetings can be stressful. Investigators should be aware of their own tone and body language, keep their personal views out of their questions and create an atmosphere in which people feel able to speak openly. If someone becomes upset, allow them time to collect their thoughts or take a break. Having water and tissues available is a small but useful touch.

Experience

Serious allegations can have lasting consequences for the business and for the individual’s career, so they call for an experienced investigator. A good investigator pieces together information from different sources, questions the employer’s own practices as well as the employee’s actions, gathers enough evidence for a fair assessment and keeps information confidential. Anyone who carries out investigations should be trained to do so.

The workplace investigation process

When a complaint or concern arises, follow your own policies and the Acas Code. A typical process looks like this:

1. Consider the information you have. Do you need written statements? Is suspension or a temporary change of duties genuinely necessary, or would it look as though the outcome has been decided?
2. Choose an investigator who is objective and has the right experience.
3. Plan the investigation: the documents to review, the people to interview and the order in which to speak to them.
4. Gather evidence, such as emails, documents, meeting notes and CCTV, and meet the employee concerned and any witnesses.
5. Analyse the evidence and consider the possible outcomes for everyone involved, including any wider changes to working practices or policies.
6. Write a report setting out the allegations, the people involved, how the evidence was gathered, the findings, a recommendation (no action, informal action or a formal disciplinary hearing) and any risks to the business.

Tell the employee under investigation what the investigation is about, who is carrying it out, the expected timescale, the need for confidentiality and what happens next. Investigations are stressful for everyone involved, so think about wellbeing support from the start.

Act without unreasonable delay. Memories fade, people leave and evidence can be lost. If there are delays, explain them to the employee. Our article on managing workplace investigations and disciplinary procedures explains how the investigation links to any disciplinary stage.

Can the employee bring a companion to an investigation meeting?

There is no legal right to be accompanied at an investigation meeting, although employees do have a legal right to be accompanied at disciplinary and grievance hearings.

Some employers allow a companion at the investigation stage as good practice or for the employee’s wellbeing, usually a colleague or trade union representative. Where an employee is disabled, allowing a support worker or other companion may be a reasonable adjustment under the Equality Act 2010.

At a disciplinary or grievance hearing, the companion can put the employee’s case, sum it up and respond to views expressed, and can confer with the employee. They cannot answer questions on the employee’s behalf.

Witnesses and their role

Anyone who saw or heard the incident may be asked for a statement or invited to an investigation meeting. Witnesses should be told that what they say is likely to be shared with the employee under investigation. If the matter goes to a disciplinary hearing, the Acas Code says the employee should normally be given copies of the written evidence, including witness statements, in advance.

Useful questions for a witness include:

• When and where did the incident happen?
• What exactly did you see or hear, who else was there and how close were you?
• Have you reported this incident, or any earlier ones?
• Did you take part in any way, for example by challenging or helping someone?
• What do you think happened, and why?

Send witnesses a copy of the meeting notes to check, and ask them not to discuss the meeting with colleagues so the investigation is not compromised.

Questions for the employee under investigation

Use open questions and give the employee time to answer. For example:

• Can you describe in detail what happened?
• What part did you play?
• Was anyone else present?
• Are you aware of the relevant policy, and how do you think your actions relate to it?
• Have you raised any concerns about this before?
• Looking back, would you have done anything differently?

Work through events in date order, keep the allegation in mind and avoid questions that sound like accusations. Ask whether there are witnesses or documents that would support the employee’s account and, if they deny the allegation, why they think it was made. Do not let previous dealings with the employee or witnesses colour the meeting.

Some employees ask to record meetings. Our article on audio recordings in disciplinary proceedings looks at how recordings can be used as evidence.

Tips for a fair HR investigation

• Make sure the investigator is fair, impartial, confident and trained.
• Follow your own procedure and the Acas Code.
• Keep information confidential and handle personal data in line with data protection law. Notes and reports may later be disclosed, including in response to a subject access request.
• Secure evidence quickly. CCTV footage is often overwritten after a short period.
• Speak early to anyone involved who is about to leave the business.
• Avoid delays, which can affect memories and suggest the matter is not being taken seriously.
• Keep the employee informed about the allegations, the timescale and any delays.
• Be prepared to ask difficult questions, including about the employer’s own policies and practices.
• Never assume guilt.

Investigations often go wrong in predictable ways. Our articles on common mistakes employers make in disciplinary proceedings and managing workplace grievances cover the pitfalls to avoid. Our employment solicitors also advise on investigations, disciplinaries, grievances and appeals, and our advice for employers covers the wider process.

If you need help planning or carrying out an investigation, book a free 30-minute consultation or call 0141 471 9166.